4 i4 THE INFERIOR EXTREMITY 



fascia, which tends to obscure them, is relaxed by passively 

 abducting the thigh. When the limb is in this position the 

 fingers can sink into the trochanteric (digital) fossa posteriorly, 

 but this depression is occluded in fractures in this neighbourhood. 

 The greater trochanter may become distorted, following its 

 implication in fractures or infective disease. Increase in size 

 can be determined and the two sides compared by encircling 

 both prominences with the fingers and thumbs. 



The lesser trochanter can be felt by palpating deeply beneath 

 the gluteal fold in the medial aspect of the thigh, when the limb 

 is extended and medially rotated. 



The iliac crests and spines have been described on pp. 237, 239. 



The Muscular Landmarks of the buttock are obscured 

 by the thick fatty superficial fascia, but the outline of the 

 glutczus maximus can sometimes be seen. Its lower border 

 crosses the centre of the gluteal fold obliquely downwards and 

 laterally, and disappears in the general contour of the lateral 

 aspect of the thigh. The upper border of the muscle descends 

 obliquely from the posterior part of the iliac crest towards the 

 apex of the greater trochanter. When the thigh is actively 

 rotated medially, a muscular elevation at once appears just 

 below and lateral to the anterior superior iliac spine. It con- 

 sists of the tensor fascia latce superficially and the glutceus 

 minimus deeply. 



The Cutaneous Nerves of the buttock are derived from numerous sources. 



(1) The terminal branches of the posterior rami of L. I, 2, and 3 cross the iliac 

 crest lateral to the sacro-spinalis, and may descend as far as the gluteal fold. 



(2) The lateral branches of the ilio-hypogastric (L. i) and last thoracic nerves 

 (p. 240) cross the crest at the iliac tubercle and supply the skin of the adjoining 

 area. (3) Branches from the lateral cutaneous nerve of the thigh (L. 2 and 3) 

 pass backwards into the gluteal region. (4) The posterior cutaneous (small 

 sciatic) (S. i, 2, and 3) gives off recurrent branches, which ascend over the 

 lower border of the glutaeus maximus. (5) The skin near the middle line is 

 supplied by branches of S. i, 2, and 3 (Fig. 124). 



Referred pain in the region of the buttock may occur in inflammatory 

 conditions of the lower part of the pleura (lateral cutaneous branch of T. 12) 

 or in irritative conditions of the bladder and rectum (posterior cutaneous 

 S. i, 2, and 3). 



The Deep Fascia of the buttock is attached above to the 

 iliac crest. In its antero-superior part, where it covers the 

 glutaeus medius, it is a strong fibrous sheet, but it splits at the 

 upper border of the maximus into two much weaker layers, 

 which enclose the muscle. On the lateral aspect of the buttock 

 these two layers increase in strength, and having received the 



